Part of the Enoch Cree First Nation west of Edmonton was used between 1942 and 1944 by the British Commonwealth Air Training Plan to teach Allied crews navigation and bombing techniques.
The First Nation says the government said practice or smoke bombs were used, but a consultant discovered that a 105-millimetre shell was found, and it's believed other munitions may have been used.
Chief Ron Morin says he's disappointed that the federal government withheld information about what types of weapons were tested until an access for information request was made.
He says the Indian Lakes golf course and its cultural grounds, which have been closed indefinitely, are historic, socially and economically significant sites. Fifty people have been put out of work, he adds.
A spokesman for the Department of National Defence says it will contact the Enoch Cree Nation for details on the discovery.
"The Department of National Defence has been working with the Enoch Cree Nation for many years on unexploded ordnance cleanup on the Yekau Lake Former Practice Bombing Range, a 520-hectare parcel of land approximately 18 kilometres southwest of Edmonton," said Daniel Le Bouthillier.
"Because the safety and security of the public is a priority for the Department of National Defence and the Canadian Armed Forces, DND will be contacting the Enoch Cree Nation for details on the discovery of this piece of ordnance."
The chief wants Ottawa to release all information about what was dropped on the land, to fully restore the area and to compensate the Enoch Cree Nation and its members.
"We know there's probably no less than 12,000 munitions still sitting in that lake bed and around it. Our independent consultant who went down to 30 feet (10 metres) shows, 'Chief you may be looking at more like 140,000 to 200,000 range.' What kind of leaching is going on from those?"
Morin says he wants independent consultants to analyze the soil and water and determine whether the dots can be connected or if it's just a coincidence that arsenic and lead levels in Enoch's water are much higher than in surrounding areas.